This chart is courtesy of Ezra Klein (h/t @viewfromthecave and @laurenist), who summarizes the results from a new World Opinion Poll. The 848 Americans polled guessed, on average, that the US spends 25 percent of the budget on foreign aid, but opined that the figure should be about 10 percent. The actual number, as you Aid Watch readers probably know, is less than 1 percent.
The chart will also be interpreted by many as showing that the US should spend more, since many citizens - who have just demonstrated they have no clue what we are currently doing - theoretically have a tolerance for more spending.

I suspect these polls just suggest that most people have a hard time comprehending very large numbers. In fact, public opinion figures on foreign aid correspond closely to another maligned area of federal spending: space exploration. In a 2007 poll, respondents apparently thought 24 percent of federal spending went to NASA, while the real number is also…less than 1 percent.

If this bit of innumeracy is just a natural human failing, perhaps it is related to what’s known in psychological research as the availability heuristic: when a rare event makes a vivid impression, we overestimate its likelihood. Maybe powerful images of earthquake survivors receiving aid in Haiti or a rocket launch remembered from childhood bias us to think these types of events are more frequent, more costly, or more significant in the context of overall spending, than they really are.